Methods and apparatus for retrieving energy readings from an energy monitoring device

ABSTRACT

An energy monitoring device including procedures for secure communication of data from the device is disclosed. The energy monitoring device includes a public/private key pair used to encrypt and/or digitally sign communications by the device. This allows the receivers of these communications to authenticate the communications to ensure that the device and/or communications have not been compromised. The energy monitoring device is further capable of communications via an ad-hoc “mesh” network, thereby facilitating communications among devices which are substantially inaccessible due to either physical or economic limitations.

RELATED APPLICATIONS

The present patent document is a continuation of U.S. patent applicationSer. No. 10/892,837, filed Jul. 16, 2004 (Attorney Ref. No. 6270/147),which claims the benefit of the filing date under 35 U.S.C. §119(e) ofProvisional U.S. Patent Application Ser. No. 60/488,700, filed Jul. 18,2003 (Attorney Ref. No 6270/115) and Ser. No. 60/554,188, filed Mar. 18,2004 (Attorney Ref. No 6270/116) and this application is a continuationin part under 35 U.S.C. §120 and § 365(c) of PCT International PatentApplication Designating the U.S. Ser. No. PCT/CA/000705 entitled “TimeCoordinated Energy Monitoring System Utilizing Communications Links”filed May 11, 2004 which claimed the benefit under 35 U.S.C. § 119(e) ofProvisional U.S. Patent Application Ser. No. 60/469,766, filed May 12,2003, all of which are hereby incorporated by reference.

The present patent document is also a continuation in part under 35U.S.C. § 120 of U.S. patent application Ser. No. 10/752,467 filed Jan.5, 2004, now U.S. Pat No. ______, which claimed the benefit under 35U.S.C. § 119(e) of Provisional U.S. Patent Application Ser. Nos.60/459,182 entitled “Access Control for Energy Management Components”,filed Mar. 31, 2003 and 60/459,152 entitled “Techniques for SecuringEnergy Management Systems” filed Mar. 31, 2003, all of which are herebyincorporated by reference.

PCT International Patent Application Designating the U.S. Ser. No.PCT/CA2004/000705 incorporated by reference the following U.S. PatentApplication which is also incorporated by reference herein:

U.S. patent application Ser. No. 10/843,256, “Wireless CommunicationsSystem Incorporating Intelligent Electronic Devices”, (Attorney Ref. No.6270/142), filed May 11, 2004, now U.S. Pat No. ______.

BACKGROUND

In facilities, e.g. buildings or installations, where a significantamount of power is used among a variety of units, it would be desirableto allow the building owner to allocate energy costs to the differentunits, i.e. consumers, within the facility. For a commercial officebuilding, these units may include the different tenants within thebuilding or the common loads for the facility, such as the elevators orHVAC systems. For an industrial facility, these units may include thedifferent production lines, machines or processes within the facility.As opposed to allocating costs based on a fixed or formulaic approach(such as pro-rata, e.g. dollars per square foot or based on thetheoretical consumption of a process/machine), an allocation based onactual measurements using appropriate monitoring devices may result inmore accurate and useful information as well as a more equitable costdistribution.

Both installation and ongoing, i.e. operational and maintenance, costsfor these monitoring devices are important considerations in decidingwhether a monitoring system is worth the investment. While monitoringdevices may be read manually, which does not increase the installationcost, manual data collection may increase on-going/operational costs.Alternatively, monitoring devices may be interconnected and beautomatically read via a communications link. However, typicalcommunication links require wiring to interconnect the devices whichincreases the installation cost. In addition, a particular tenant in thebuilding may wish to verify that they are being billed correctly byreading the energy meter or other energy monitoring device that isaccumulating their energy usage. This may be a straightforward, althoughlabor intensive and cumbersome, process with a typical energy meterwhich provides a display viewable by the tenant.

Emerging wireless mesh (or ad-hoc) networking technologies can be usedto reduce the installation costs of monitoring devices while providingfor automated data collection. Also called mesh topology or a meshnetwork, mesh is a network topology in which devices are connected withmany redundant interconnections between network nodes. Effectively, eachnetwork node acts as a repeater/router with respect to receivedcommunications where the device is not the intended recipient in orderto facilitate communications between devices across the network. Usingwireless interconnections permits simpler and cost-effectiveimplementation of mesh topologies wherein each device is a node andwirelessly interconnects with at least some of the other devices withinits proximity using RF based links. Mesh networking technologiesgenerally fall into two categories: high-speed, high bandwidth; and lowspeed, low bandwidth, low power. The first category of devices aretypically more complex and costly that the second. Since energymonitoring does not typically require high speed/high bandwidthcommunication, the second category of devices is often sufficient interms of data throughput.

Energy monitoring devices may include electrical energy meters thatmeasure at least one of kWh, kVAh, kVARh, kW demand, kVA demand, kVARdemand, voltage, current, etc. Energy monitoring devices may alsoinclude devices that measure the consumption of water, air, gas and/orsteam.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a block diagram of a commercial building incorporatingthe system of the present invention.

FIG. 2 depicts a block diagram of the internal circuitry of an exampleof an energy monitoring device of the present invention.

FIG. 3 depicts a block diagram of a first procedure retrieving averified energy reading from the energy monitoring device of the presentinvention.

FIG. 4 depicts a block diagram of a second procedure retrieving averified energy reading from the energy monitoring device of the presentinvention.

FIGS. 5-6 depict an exemplary method of mounting a monitoring deviceaccording to one embodiment.

FIGS. 7-8 depict exemplary commissioning reports according to oneembodiment.

FIGS. 9A-9C depict an exemplary CT locking device.

FIG. 10 depicts exemplary voltage waveforms and time relationships forseveral possible current waveforms according to one embodiment.

FIG. 11 depicts an exemplary voltage displacement device for use withthe disclosed embodiments.

FIG. 12 depicts a block diagram of an alternate commercial buildingincorporating the system of the present invention.

FIG. 13 depicts an exemplary process for using assumed data values incomputations according to one embodiment.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

Herein, the phrase “coupled with” is defined to mean directly connectedto or indirectly connected through one or more intermediate components.Such intermediate components may include both hardware and softwarebased components. Further, to clarify the use in the pending claims andto hereby provide notice to the public, the phrases “at least one of<A>, <B>, . . . and <N>” or “at least one of <A>, <B>, . . . <N>, orcombinations thereof” are defined by the Applicant in the broadestsense, superceding any other implied definitions herebefore orhereinafter unless expressly asserted by the Applicant to the contrary,to mean one or more elements selected from the group comprising A, B, .. . and N, that is to say, any combination of one or more of theelements A, B, . . . or N including any one element alone or incombination with one or more of the other elements which may alsoinclude, in combination, additional elements not listed.

In general herein, a public key is a number, formula, algorithm,function, etc. that is made, or intended to be, publicly available, i.e.made available to any user that wants it. A private key is a number,formula, algorithm, function, etc. that is intended to be kept privateand is protected in some way from access. This protection may be in theform of secrecy, an enclosure, encryption, difficulty in access, etc.The more difficult it is to circumvent the protection, the better,however it will be appreciated that the utility of the disclosedexamples is not dependent on the quality of the protection the privatekey.

An energy monitoring device that is designed to transmit its measurementvalues may not be accessible to be manually read by a person. This maybe due to the fact that the energy monitoring device does not have adisplay or is otherwise physically inaccessible, and although the devicemay provide a communications pathway (wired or wireline) allowing it tobe accessed by the energy provider, the device may not provide a directcommunications pathway for the user. This causes a problem in that theuser/consumer of the energy being monitored by the energy monitoringdevice may be left with no way of verifying that they are being billedaccurately for the usage that their respective energy monitoring deviceis measuring. For instance, a configuration error may result in the userbeing billed based on an incorrect or mis-configured energy monitoringdevice or the user may simply not trust the energy provider to providean accurate accounting of energy consumed.

The following description details various mechanisms for verifying theintegrity of readings taken from electrical monitoring devices which arein communication with a central computer through a mesh network. It willbe clear to those skilled in the art that the mechanisms defined hereinare also applicable to monitoring other parameters indicative of energyconsumption.

Public/private keys may be used for authenticating a message sent fromone computer to another computer over communications pathways such asthe Internet. In general, a message can be authenticated by performing afunction (such as a hash) on the message data with a private key of onecomputer. A second computer can then verify the origin of the message byperforming a corresponding function on the results of the first functionand the message data using the first computer's public key.

FIG. 1 depicts an exemplary commercial office building 100 for use withthe disclosed embodiments. The commercial office building 100 has anumber of floors 110. Each floor may contain an electrical room 130.Alternatively there may be more than one electrical room 130 per flooror only one electrical room 130 per a number of floors. Within eachelectrical room 130 there may be one or more energy monitoring devices120 within an energy monitoring system 101. It will be appreciated thatthe location of the energy monitoring devices 120 is implementationdependent and that they need not be located in an electrical room 130.The energy monitoring devices 120 communicate among each other to form amesh network, depicted in FIG. 1 by multiple communications links 140shown between the energy monitoring devices 120. It will be appreciatedthat fewer or more communications links 140 may be used betweenmonitoring devices 120 and that the availability of a communicationslink 140 between any two monitoring devices 120 may fluctuate dependingupon conditions such as interference, etc. Repeaters 155 may also beprovided to facilitate communications between two devices 120 which maynot otherwise be able to communicate due to distance, interference, etc.Alternatively, one device 120 may have two antennas which operate atdifferent power levels, gains, frequencies, modulation schemes, etc. toovercome interference, distance, etc. One of the antennas may beconnected to a long cable (such as a coaxial cable) in order that theantenna may be located remotely from the device 120 in a more effectivelocation for transmission/reception than the device 120. Alternatively,the architecture may provide a wireline segment 156 where communicationsbetween two devices are not possible otherwise. This may happen due todistance, interference, shielding, etc. The mesh network may use thewireline segment 156 in a similar fashion to the communication links140. The wireline segment 156 may be implemented using power linecarrier techniques over the office building 100 power lines or usingstandard wireline communications/networking architectures such asRS-485, RS-232, Ethernet, etc.

The device 120 may facilitate the replacement of its antennas such thatfor a given installation location, flexible, such as rubber encased orflexible wire, adjustable, directional, high gain, or differentpropagation pattern antennas may be substituted to facilitate morereliable communications. Further, antenna enhancing devices or deviceswhich enhance RF transmission by utilizing proximate structural elementssuch as metal casings, glass windows, etc., may also be used

The mesh network also encompasses a gateway 150 which facilitatescommunications with a computer 160 or other computing device. Thecomputer 160 may communicate energy data and other data over a LAN 170.The computer 160 and gateway 150 communicate over a serial or other formof communication link. Alternatively, the gateway 150 may interface withthe LAN 170 directly and the computer 160 may be connected to the LAN170 in a different part of the building 100 and communicate with thegateway 150 over the LAN 170. The computer 160 may receive a timereference from a GPS satellite 185. Alternatively, the GPS satellite 185signal may be received by an energy monitoring device 120, gateway 150or repeater 155 within the mesh network. In this alternate case, thetime within the alternate device becomes the reference for the energymonitoring system 101. The LAN 170 may interface to a WAN 171 such asthe Internet. The gateway 150 may, for example, be located in a chiefengineer's office where a connection to the LAN 170 is readilyavailable. There may be more than one gateway 150 in the energymonitoring system 101 facilitating extraction of data from the system atmore than one point in the mesh network. The gateways 150 maycommunicate over the LAN 170 to a concentrator that aggregatesinformation from all the gateways.

With present mesh networks it is often difficult to determine thehealth/status of the network. Typically, only basic information isavailable from any given node, such as the ability of the node tocommunicate with the gateway and the signal strength for closest node,both of which give no indication of redundant paths or communicationerror rates, or other more detailed status information. Often after anetwork is installed, unhealthy networks, e.g. network with one orfaulty links or devices, are identified through missing data or lowpercentage of responses to requests. The need exists to have an easy lowcost way to determine health/status of the network especially duringinstallation of a system.

In one embodiment, a data aggregation device, which may be a portablecommunications device 180, or other device coupled with the mesh networksuch as the gateway 150 or computer 160, or software executing thereon,provides the ability to gather network status/statistical informationfrom the mesh network via self/automated reporting by the devices whichmake up the network. Such self-reported data may include perceivedsignal strength, delivery delays, multiple or confusing responses,non-responsive or slow responding nodes, communications errors, etc.Further, this data may include both current and historical datacollected over a period of time. Such reporting facilitates theidentification of weak network links, failing nodes, redundant paths,etc. The reporting may also take place via the display or localcommunications connection of the particular device to allow a physicallyproximate user to assess and view the network status as perceived bythat particular device. In an alternate embodiment, each device mayreport the status information of other devices as well, such as othernodes/devices which are proximate to the particular device. At the pointof data aggregation, this reported data may be collected/aggregated andreported to a user to present an overall network status of the entirenetwork, or a particular portion thereof, such as by a graphicalpresentation or the like which shows failing links, links with higherror rates, low signal strength, etc. possibly using colors or othervisual indicators.

In an alternate embodiment, rather than rely on a self reportingmechanism, or in addition thereto, diagnostic packets may be sent orrequested from each node over the wireless link containing data used bythe gateway to identify weak or failing links or nodes in the radionetwork. The diagnostic packets may contain such information as signalstrength of all neighboring nodes in priority of use and number ofredundant paths. This data would then be used by the gateway todetermine if additional repeaters are needed in specific locations. Inone embodiment, diagnostic packets are capable of being directed overparticular network paths of the mesh network to focus diagnosticactivity on particular areas of the network.

Where weak links or troublesome nodes are discovered, measures could betaken to increase communication reliability. For nodes that have weaklinks to the rest of mesh network, for example communications may beattempted more often in an effort to effectively increase the chancesthat some of the communications will get through during periods ofreliable connectivity and causing the mesh network to seek better linkswith this device.

Many issues with mesh networks occur upon installation of the networkand may be resolved at that time, prior to actual use and reliance onthe network. For example, during the installation of a large number ofmeters, such as can be found on a commercial building meter installation(typically 100 meters or more), a fairly high probability exists thatone or more of the devices will be installed incorrectly. Furthermore,some devices may have limited error detection capability due tolimitations in their memory capacity/code space and are only be able todetect simple and obvious errors. Typical errors which simpler devicestypically detect include: wrong phase connections, reversed CTconnection or bad CT and phase connections (open/shorted).

In one embodiment, the capability to generate an automated commissioningreport from the different devices is provided. The commissioning reportis generated by first obtaining assorted real time device data from allof the operating devices and then analyzing the real time values forvalidity. The real time device data may include RMS current and voltagereadings, frequency, apparent (VA) power, real (W) power and reactive(VAR) power and power factor. Using a combination of these values, inconjunction with the measuring mode (delta or wye), angles can bedetermined between voltage and current phases. For example, if the realpower is negative and in the installation it is known to be positive,i.e. since power is being delivered, this may indicate that the currenttransformer (“CT”) could be reversed. For devices that can automaticallycompensate for a reversed CT, a warning would be provided indicatingthat the CT phase is reversed.

In this embodiment, every device in the installation is automaticallyinterrogated when the device is initially detected in order to providean entry for the commissioning report. Expert system software isprovided at the point of data aggregation which uses common senserelationships to analyze the data and determine if the readings arereasonable. The installer will go over the commissioning report andevaluate each error or warning for validity. For example, if voltage andcurrent from I2 are reported to be zero on a floor/panel, and theinstaller knows there are no loads on the circuit, then the reading isreasonable. However if there is expected to be a reading, then there issomething wrong with the CT, connections or configuration and theinstaller can take corrective action. An exemplary table basedcommissioning report is shown in FIG. 7.

The commissioning report may be further enhanced by providing relativephase angles between all the current and voltage phases. Thisinformation may be provided by a device such as the ION 6100 powermeter, manufactured by Power Measurement, Ltd., located in Saanichton,British Columbia, Canada. Using the phase angles, swapped current orvoltage phases may be easily determined. To simplify the presentation,the commissioning report may simply provide a vector diagram (as foundon ION 7500 power meter, also manufactured by Power Measurement, Ltd.)for each device with an appropriate OK, WARNING or ERROR message. Thiswould reduce the clutter of a large number of real time reading values.FIG. 8 shows an exemplary vector based commissioning report.

The installation of mesh networks using monitoring devices, such as theION 6100 mesh network based power meter, can be complicated byintermittent network connections due to marginal transmission andreception of data over the network. Typically, during the commissioningof the system, all that can normally be done is to verify that eachdevice in the network communicates with a central gateway. Thisverification simply tells the installer that the system is currentlyworking properly, but it does not tell how much operating margin theradios have. For low cost devices, it is usually not feasible to includemeasurement of signal strength.

The operating conditions of a mesh network radio can change due to nearbody effects, temperature, interference, fading and multi-path, etc. Ifnode reception, i.e. signal strength or connection quality, is close tothe operating limit of the radio, then small changes of the operatingconditions may render a node non-communicating.

In one embodiment, the use of a variable power mesh network node isprovided to validate the correct operation of the system at a reducedpower level. During commissioning, the system is switched to a lowerpower mode which operates the radios at a lower power level than theradios are normally capable of. Once the system has been verified to befully operational (which may require the installation of appropriaterouters to complete the network), the system is switched to the normaloperating mode at the normal radio power. During normal operation, themesh network node power will be increased to a higher (normal) powerlevel assuring that the reception and transmission of mesh network datais well above any marginal radio operating parameter.

In yet another embodiment, the monitoring devices feature the capabilityto be located a inside or proximate to a circuit breaker with themonitoring device's current transducers being coupled with the breaker'sloads and sending data to the monitoring device/meter. The currenttransducers also feature mesh network capability, i.e. RF communicationscapabilities as described herein, and communications between thedevice/meter and the current transducers is accomplished via a meshcommunications network or other medium. In this embodiment, thedevice/meter is physically configured to fit within a particularform-factor of the breaker panel.

In yet another embodiment, the mesh network may include nodes mounted toelevators, or other moving mechanical systems, and utilizing themovement of the elevator to bring the elevator-mounted node within acommunications-proximity to portions of the mesh network which areotherwise inaccessible. The elevator mounted node may act as a store andforward device facilitating communications between other network devicesas connections are established and lost due to its movement. Theelevator mounted node may store data from particular devices until theelevator moves to another location where forwarding of the data ispossible or alternatively, the elevator mounted node may use alternatecommunications means such as higher power RF or wireline communicationsto forward the data.

In yet another embodiment, the mesh network of monitoring devicesfurther include a capability to share common area usage charges based onactual or more closely approximated usage of common areas. Themonitoring devices or central aggregation device may feature thecapability to discern usage of common areas by particular tenants, or atleast make approximations of such usage. Where reasonable approximationsof particular tenant usage may be determined and associated withparticular consumption, that consumption may be appropriately charged tothe particular tenant. For example, power consumption by the elevatorsmay be apportioned to tenants by the floors which they occupy such thata tenant which occupies multiple floors or is a frequent elevator useris apportioned a more appropriate amount of the charges associated withoperating the elevators. Other methods of approximating particulartenant usage of common areas may rely on building access identificationscards and their use at particular access points throughout the facilityor RF enabled identification badges which permit tracking of tenantmovement throughout the facility. Further, temperature sensors, or othercoupling with environmental control systems, may be provided to measureHVAC usage in particular areas to properly apportion those costs.

A user 190 may transport a portable communication device 180 around thebuilding 100. This portable communication device 180 may be used to readenergy registers from the various energy monitoring devices. Theportable communication device 180 and the energy monitoring device 120may both have indicators (such as LEDs) on them that light, or otherwisesignal, when communication is established between the two devices. Thisindicates to the user that they are in communication with the correctenergy monitoring device 120. In addition, the portable communicationdevice 180 may read a secondary register from the energy monitoringdevice 120 which is a hash of the energy registers and a pattern such asthe private key of the energy monitoring device 120. If the pattern isknown only to the energy monitoring device and a system such as abilling system within a utility, the registers within the portablecommunication device will be difficult to tamper with without detection.The secondary register may appear to the user of the portablecommunication device 180 as just another register such that the user isnot aware that the secondary register may be used for tamper detection.The portable communication device 180 may be a handheld meter reader.

In one embodiment, a handheld device is provided for performingnetwork/device related tasks, such as optimizing monitoring device (orantenna) locations for optimal communication performance, performingroutine monitoring of network status, determining or monitoring forspecific device availability or activity, determining device locations(by proximity or by using GPS capabilities), communicating with devicesvia the mesh network and/or direct/local device interfaces, such as forsetting up/initializing devices, and acting as a mesh enabled datadisplay.

When installing wireless meters/nodes it may be advantageous for theelectrician or commissioning engineer to have a separate handheld radiothat is used to determine suitable positioning of the devices beinginstalled. The handheld radio would be able to communicate with thenetwork being installed and have a faster rate of communication with thegateway 150. The rate of communication with the gateway 150 could beconfigurable to suit all sizes of networks. The handheld radio may havea display or some other user interface such as LED's to help determineradio link quality into the network.

Alternatively each device being installed could have a deployment modewhere its rate of communication to the gateway 150 would be faster for aperiod of time, thereby giving the installer more feedback as to thesuccess and quality of the installation. The device could have a buttonthat is used to activate the deployment mode for this period of time.The installer would then be able to move the device around until asuitable position is found, with the device and/or gateway determiningand reporting the status of the communications link at a more frequentrate than might be had in the normal operating mode. The installer wouldbe aware of a suitable position through data reported by the device,such as via LED's or the display on device. Deployment mode may onlylast for a period of time that is sufficient to find acceptable locationand communicate with the network. The deployment mode may automaticallyshut off to prevent installed devices being left in deployment mode.

In both of the cases above the network would have to be installed asfollows:

The gateway 150 is installed.

1. Devices can then be installed from the gateway 150 out so that aseach device is installed, they are able to communicate with the gateway150; and

2. If it is not possible to install the devices, then temporaryrepeaters are put in place of where devices or repeaters will have to beinstalled to complete the network.

Alternatively, the gateway 150 may have a deployment mode wherestatistics are gathered for each node in the network. The gateway mayperform ping statistics on nodes, request diagnostic packets containingsuch things as signal strength, # of hops etc. After meters areinstalled, the gateway would then have to be taken out of deploymentmode to gather energy information.

Locating installed devices may prove to be difficult especially if ameter is installed in a location different than the intended location.To assist in locating devices each meter could be outfitted with GPSchips. The location of the device could then be reported through thewireless link. A handheld GPS unit could then be used to assist inlocating the device.

FIG. 2 shows a block diagram of an energy monitoring device 120according to one embodiment. The energy monitoring device 120 includeselectrical current interface circuitry 210 and electrical voltageinterface circuitry 270. The electrical current interface circuitry 210and electrical voltage interface circuitry 270 are operative tointerface with power conductors which supply electrical energy to acertain load or area of the building 100. This interface may be director through appropriate current or voltage transformers. In alternativeembodiments, the energy monitoring device may lack either the electricalcurrent or electrical voltage interfaces 210, 270 depending upon theimplementation and monitoring requirements of the device 120. The energymonitoring device 120 further includes an analog to digital converter220, a micro-controller 230 coupled with the analog to digital converter220, and RF communications circuitry 240 coupled with themicrocontroller 230. The electrical current interface circuitry 210 andelectrical voltage interface circuitry 270 scale the signals from thepower conductors to voltage levels compatible with the analog to digitalconverter 220. The analog to digital converter 220 provides digitalrepresentations of the voltage and current in the power conductors tomicrocontroller 230. Using these signals, the microcontroller 230calculates at least one power parameter such as kWh, kVAh, kVARh, kWdemand, kVA demand, kVAR demand, etc. The microcontroller 230 transmitsthis power parameter through RF communications circuitry 240 through themesh network and gateway 150 to computer 160. The computer 150 may sendconfiguration and command data (such as demand reset) to the energymonitoring devices 120 through the mesh network. The microcontroller 230also maintains time for the energy monitoring device 100 in a memoryregister 280 which may be internal to and/or external to themicrocontroller 230. The microcontroller 230 also maintains a privatekey 281 in internal and/or external memory. The energy monitoring device100 also contains a power supply 260 which may interface to the samevoltage signals as the voltage interface circuitry 270 or to analternative power source. The power supply 260 may incorporate a batteryor capacitor to facilitate operation when operating power is lost. Thepower supply 260 may also incorporate crystal radio type circuitry as analternate source of operating power such that RF power present fromlocal AM radio stations may be utilized to power the energy monitoringdevice 120. Additional circuitry 250, such as wireline communications,I/O circuitry, etc. may also be provided in the energy monitoring device120. A label 282 is provided on the outside of the energy monitoringdevice 120. The label may provide the public key corresponding to theprivate key 281. Alternatively, the public key may be shown on a displaycoupled to the microcontroller 230 or periodically broadcast over thecommunications links 140 forming the mesh network, either automaticallyor in response to a request. In one embodiment, the public key andassociated private key may be periodically changed by themicrocontroller 230. The microcontroller 230, may use A/D 220 readings,RF noise readings, etc. as random numbers to generate thesepublic/private key pairs or, alternatively, the key pairs may beinserted during manufacture or may be input to the energy monitoringdevice 120 using other methods.

In one embodiment, a voltage displacement device is utilized to allowany piece of monitoring equipment to be connected to a voltage conductorwithout the need to power down the line to be monitored. This piece ofequipment could be an integral part of the monitoring devices voltageleads or a separate device that would allow for a galvanic connectionbetween the voltage source and the monitoring device. An exemplaryvoltage displacement device 1102 is shown in FIG. 11 attached to a powerline 1104. The voltage displacement device 1102 pierces the powerconductor 1104, in a safe and insulated manner, to provide a means ofpowering the monitoring device as well as providing a signal to monitorand/or measure. The device 1102 is clamped and locked to the powerconductor 1104 utilizing a locking/clamping mechanism 1106 in a mannerthat would require a tool for removal, thereby preventing unauthorizedpersons from tampering or removing the connection. Even when localelectrical codes, procedures and/or standards require powering down aconductor before adding a connection to it, the voltage displacementdevice may save installation time and cost since no splicing, terminalconnections, etc. are necessary to make the connection.

In one embodiment, a power meter is provided which includes multipleradios for redundant operation in case of a failure or to facilitatecommunications over multiple RF channels simultaneously. Alternatively,a low power and a high power radio, possibly similar to the low/highpower radio described above for device installation, may be provided,wherein the device determines the optimum radio to use based on ambientenvironmental conditions, time of day or other trigger.

If, for some reason, nodes in the main radio network stop communicatingenergy/power data there may be an alternate method to extract datamanually or through some other low cost method. Due to the nature ofmesh networks if nodes in the middle of the network lose power, allnodes that communicate through those nodes may also stop communicating.Using a point to point radio technology would enable a person to go fromfloor to floor collecting energy/power data from the non-communicatingdevices until the mesh wireless network problem is resolved. Inparticular the second radio technology could be Bluetooth, 802.11x (a, bor g), infrared, or similar networking technology, so that the datacollector could use a handheld device to communicate with a singledevice if the address is known (point-to-point).

In one embodiment, the gateway device 150 may provide a firewallcapability, or this capability may provided by a separate devicelogically located so as to be able to control and contain networktraffic, which prevents unauthorized access to the mesh network from anexternal network, such as via the gateway device. The firewall devicemay further permit limited unauthenticated wireless access or limitaccess based on the level of security or level of trust in a givenentity or method of access.

Often in establishments, the department responsible for internalnetworks will be wary of attaching devices to their internal network.However, this department may be receptive to providing a networkconnection to a demilitarized zone or directly to the internet. In thiscase the firewall within or coupled to the gateway protects the gateway150 and mesh network devices from unauthorized access. The gateway mayreport to the computer (which may be within the corporate network)through protocols such as SMTP, HTTP, etc. which most corporatefirewalls do not block.

Often there is no Ethernet connection where the gateway is to beinstalled. Instead of running a wired connection to the demilitarizedzone, a secure wireless technology such as WI-FI may be used.

In yet another alternative embodiment, the capability for a monitoringdevice or other node to act as a gateway for legacy devices, which donot feature the capability to communicate via the mesh network, isprovided. The gateway-enabled device may act as a simple conduitallowing bi-directional communications with the legacy device as if thelegacy device were itself on the network. This may be accomplished viaprotocol encapsulation. Alternatively, the gateway-enabled device mayact as a master device, server or other intermediary which mediatescommunications between the network and the legacy device(s). Forexample, the gateway-enabled device may aggregate data retrieved frommultiple legacy devices and pass the aggregate onto the network.

In RF challenged zones, i.e. where RF based communications aredifficult, or for supporting legacy devices, it may be desirable tocommunicate to meters via the RS-485 serial bus. In one embodiment, agateway device is provided that supports both wireless technology andmultiple/single RS-485 connections for legacy devices or in areas werewireless does not work. The gateway device, as described, may act as asingle data collector for multiple nodes communicating via RS-485 andwireless links. The gateway device may be an application specific devicefor bridging other devices onto the mesh network or may be an additionalfunction provided by a mesh network node, such as the monitoring devicedescribed above.

In yet another embodiment, a monitoring device or other node device isprovided with flexible power options allowing it to draw operating powerfrom various sources, without interfering with those power sources. Thisadds to the flexibility of the device to be placed in locations whichmay not have convenient sources of operating power, the sources ofoperating power may not be reliable or stable, and/or the sources ofoperating power are the same as that being monitored and isolation ofthe device is desirable. Such sources of electrical power may includeemergency power sources such as power for exit or emergency lightingsystems, solar power (via a window or ambient lighting), telephonesystem power, battery power, RF power (similar to the operation of RadioFrequency Identification Devices (“RFID”) or crystal radio sets) orcombinations thereof. In this way, there is reasonable assurance thatthe device will receive a constant uninterrupted supply of operatingpower. Such devices may be further provided with flexible mountingoptions such as the ability to be mounted to a light bulb socket or wallsocket/outlet. The ability to lock the device in place and drawoperating power therefrom may also be provided. An example repeater 155that may be plugged into a wall 506 outlet 502 having one or more powersockets 504 is shown in FIGS. 5 and 6. The repeater features an antenna508 and power connectors 510. In this configuration, the repeater 155draws power from at least one of the sockets 504 and is secured in placewith a replacement screw 514 for the wall outlet 502. The repeater 155can thus not easily be removed either accidentally or intentionally. Thescrew 514 may incorporate a one-directional drive engagement to furtherdiscourage removal. The repeater 155 may also provide pass throughoutlets 512 such that the outlet 502 can still be used. In an embodimentwhich fits into a light socket, a pass through socket may be provided toallow the socket to be used for illumination purposes.

In one embodiment, mesh network enabled current transducers ortransformers (“CT's”) include a physical security mechanism to preventor indicate tampering and/or removal of the CT from the power line beingmonitored. FIGS. 9A-9C depicts an exemplary CT 900 having a revenue lockmechanism 955. Effectively, the CT includes two interlocking portions925 930, each of which come together to encircle the power line 903 tomeasure the current passing there-through. The interlocking portions 925930 each feature a locking hole 955. The locking holes 955 of eachportion come into alignment when the portions 925 930 are assembledaround the power line 903 thereby allowing a sealing device 950, such asa lock or locking wire, to be fed through both holes 955 preventingremoval of the CT without breaking the locking mechanism 950 and/orcausing indication of tampering.

In yet another alternative embodiment, the capability to update and/ormodify the firmware of a monitoring device or other mesh network nodevia a mesh network is provided. In operation, the particular monitoringdevice(s) or other mesh network node(s) to be upgrade/modified may beinstructed to enter an upgrade/modify mode. Upgraded or modifiedsoftware/firmware may then be transmitted via the network to the deviceas one or more packets. The device(s) receives and assembles thesepackets into a memory, re-requesting packets that are received witherrors and determining and re-requesting missing packets. Once the newcode has been fully transferred, the device is instructed to beginexecuting the new code. Prior to executing the new code, the device mayvalidate or otherwise authenticate the code and may further performfunctions to ensure that the device can recover should an error occur,such as by performing a data backup operation. In an alternateembodiment, the special upgrade mode is unnecessary. In this case, thepackets of new code contain an indicator to the device as such. When thedevice sees such packets, it writes them to its memory store andassembles the complete code, re-requesting errant packets and trackingand re-requesting missing packets. Once all of the packets have beenreceived, as determined by an indicator which tells the device how manywere to be received or by an packet denoted as the last packet sent, thedevice automatically switches over to the new code. Prior to switchingover to the new code, the device may validate the new code, or otherwiseperform an authentication. Further, the device may perform a backupoperation of any stored data to ensure that recovery is possible if anerror occurs.

In one embodiment, a monitoring device is provided which is capable ofutilizing assumed voltage readings in situations where it is notpossible to determine actual voltage readings from the circuit beingmonitored. This capability allows the monitoring device to operate untilit becomes possible to connect it to the voltage terminals of thecircuit to be monitored, or operate indefinitely without connection tothe voltage terminals, depending upon the application. When installingthe energy monitoring device 120, it is often necessary to power downthe circuit to be monitored so that voltage connections can be made tothe energy monitoring device. Otherwise, the installer may be exposed tohazardous voltages and/or the device 120 may experience an unexpectedpower surge on its inputs upon connection, thereby damaging the device.However, installation of the current connections can often beaccomplished with the circuit energized when using non-contact sensors,such as “clamp-on” CTs which rely on induced current flow, as the riskof injury or damage is lessened.

Therefore, the energy monitoring device 120 according to the presentembodiment provides the ability to estimate power and/or energy readingswhen only the current inputs are connected. As described, thisestimated-operation may be used on a temporary or permanent basis. Ifused on a permanent basis, the energy monitoring device 120 may beprovided without voltage inputs so as to lower manufacturing costs. Thismay occur, for example, where the application demands may be met usingassumed voltage values and, accordingly, the user does not wish to payfor or install fully functional devices 120.

In order to estimate power and/or energy readings, several techniquesmay be used. In one embodiment shown in FIG. 13, the energy monitoringdevice 120 may be programmed with an assumed voltage and/or power factorbased on the particular load it is monitoring (1302). The device 120 maybe programmed prior to, or after, connecting the current inputs to thecircuit to be monitored (1304). The assumed value(s) is/are stored in amemory within the device and used by the processor as the basis forcomputing other data regarding the monitored circuit, as will bedescribed. Programming assumed values into the device 120 may beaccomplished directly using direct communications inputs provided by thedevice 120 or through the mesh network or other network communicationsinput. Once programmed, the device switches into an assumed-value modeof operation, either manually or automatically, as described above(1306). The assumed voltage and/or power factor values may then beutilized by the device 120 to perform the requisite power and/or energycalculations (1308). The computed results may then be reported as perthe normal operation of the device 120 (1310). As noted above, thereported results may include an indicator which indicates that thecalculations were based on assumed values and may further indicate amargin of error as such. In an alternate embodiment, multiple powerfactors, for different load currents, are provided and the energymonitoring device 120 interpolates between these power factors based onthe current present in the circuit being monitored. For example, theenergy monitoring device 120 may be provided with an assumed voltage of480 VAC, and an assumed power factor of 0.84 at full load current (e.g.40 Amps), an assumed power factor of 0.8 at ¾ load current and anassumed power factor of 0.72 at ½ load current. The energy monitoringdevice 120 may then interpolate the power factor to provide interpolatedvalues for use in power and/or energy calculations based on actualcurrent values which may range between the programmed assumed values oroutside of them.

Alternatively, the energy monitoring device 120 may be programmed withan assumed voltage waveform and time relationship to the actual waveformrepresentative of the actual current present in the circuit beingmonitored. FIG. 10 shows several example voltage waveforms and tinerelationships 890 for several possible current waveforms 895. The energymonitoring device may use techniques such as fuzzy logic, artificialintelligence, point by point comparison, etc. to determine the closestmatch current waveform in a stored suite of waveforms and then use thecorresponding voltage waveform including the assumed phase or timerelationship to the current waveform in power and/or energycalculations. In yet another alternative embodiment, an assumed voltagemagnitude may be programmed into the energy monitoring device 120 overthe mesh network or the energy monitoring device 120 may be manufacturedfor a given voltage. This voltage magnitude may then be applied to theassumed voltage waveform during the calculation of power and/or energy(ie., each point in the assumed voltage waveform may be multiplied by aconstant such that the rms value of the voltage waveform used in thepower/energy calculations is the same as the voltage magnitudeprovided).

Further, when the monitoring device 120 is operating using assumedvoltage data, an indicator may be appended to all calculation results toindicate to a user or a data aggregation system that the data that themonitoring device 120 is producing is based on assumed values. Further,a visual indicator on the monitoring device 120 itself may indicate suchoperation as well.

In one embodiment, the assumed values are stored in a memory within thedevice 120 and referenced by the device 120 for performing calculationsas described when the device 120 is placed in a “assumed voltage” modeof operation, either automatically or manually by a user via thedevice's 120 user interface or remotely over a network. This mode ofoperation may automatically be activated when the device 120 is suitablyprogrammed with assumed data values and the device receives inputs onits current inputs but not on its voltage inputs, such as when thevoltage inputs are not connected or the inputs or connections to thecircuit fail or otherwise become disconnected. Further, the assumedvalues may be stored as digital values which bypass the device's 120analog to digital converter to be directly input into the processor ofthe device 120 or the assumed values may be stored in an analog form andact as pseudo inputs to the analog to digital converter when actualvoltage measurements are not present. In one alternative embodiment,assumed voltage values are input into the monitoring device 120 byattaching a dummy voltage generator to the voltage inputs of the device120 to feed an assumed voltage value to the device 120. This has theadvantage of allowing the use of assumed voltage values on older devices120 which lack the capability to be programmed to do so.

In addition to using the steady state current waveform to determine anappropriate voltage waveform and/or phase relationship to assume, theenergy monitoring device 120 may analyze current waveforms duringstartup conditions, transients, surges or sags in current level todetermine the type(s) of loads that are being powered. Assumed steadystate voltage waveforms/phase relationships may be selected based onthese conditions only or in combination with steady state currentreadings. Refer to PCT International Patent Application Designating theU.S. Ser. No. PCT/US/______ entitled “METHODS AND APPARATUS FORMONITORING POWER FLOW IN A CONDUCTOR”, (Attorney Ref. No. 6270/149)filed Jul. 16, 2004, herein incorporated by reference.

Several procedures for retrieving energy related data from energymonitoring devices 120 in the building 100 will now be discussed. Itwill be appreciated that the described procedures may be used alone orin combination without departing from the spirit and scope of theinvention.

FIG. 3 shows a first procedure for retrieving energy related data froman energy monitoring device 120. The energy monitoring device 120 may beinstalled and interfaced to voltage and current signals (block 300) inorder to monitor or measure at least one power parameter (block 310).The power parameter may be kWh, kVAh, kVARh, kW demand, kVAR demand, kVAdemand, voltage, current, etc. The energy monitoring device contains anumber of registers which store various measured and computed datavalues. This installation may be in electrical room 130 or any otherappropriate installation location. The energy monitoring device createsa security register data (block 320) and stores this data in a securityregister in the device 120. This security register data is created bythe operation of the private key 281 on the measured power parameter(s),for example, the private key 281 may be hashed together with themeasured power parameter(s). The private key 281 may be any of thepieces of information described above. The register (including thesecurity register) contents are then retrieved from the energymonitoring device 120 (block 325). The registers may be retrieved usingany appropriate method. Some example methods include reading with aportable computing device 180 over a wireless link, manual recording onpaper or into a handheld device or direct communication over acommunication link to a central computer. The retrieved registercontents are then returned to the utility or other entity that bills forenergy usage (block 330). This may be accomplished by returning thepaper or portable computing device 180, or storage media therefrom, tothe utility or receiving the register contents over a communicationslink at the utility. The register contents, including the securityregister data from the security register, are then downloaded into acomputer (block 340) where the register contents are authenticated usingan appropriate public key (block 350) or using a shared private key. Thepublic key may be any of the pieces of information described above.

Using this procedure, the possibility of an individual (such as a meterreader) tampering with energy readings is reduced due to the fact thatthe individual would either have to know the private key of the device,or be able to compromise the particular public/private key algorithmused in order to change the energy readings without detection.

FIG. 4 shows a second procedure for retrieving power parameters from anenergy monitoring device 120. This procedure may be appropriate for usewhen a consumer of energy wishes to verify that they are being billedcorrectly for energy usage. The energy monitoring device is installedand monitors at least one power parameter (blocks 300, 310) in a similarfashion as described in the previous procedure. The energy monitoringdevice 120 signs the power parameter(s) (block 400) utilizing a digitalsignature and transmits the power parameter(s) and signature over thenetwork (block 410). As used herein, to “sign”, or alternatively,“digitally sign”, a message/document means to generate or otherwiseappend a “digital signature” to the message/document. A digitalsignature is an electronic signature appended to a message/document thatcan be used to authenticate the identity of the sender of amessage/document, the signer of a document/message, ensure that theoriginal content of the message/document that has been sent is unchangedand/or prevent repudiation of the document's/message's contents by thesender. The signed document/message, with or without the digitalsignature may, but need not, be encrypted, either before or aftersigning. A digital signature is typically generated based on thecontents of the document/message and the sender's private key of thepublic/private key pair. Upon receipt, the receiver of the message“authenticates” the message contents using the sender's public key. Thenetwork may be the mesh network previously described wherein the packetsare transmitted via other energy monitoring devices or any otherappropriate communications means. This information is received by acomputer which makes the information available to a consumer of energy(or other entity that wishes to verify energy readings). For example,the information may be made available by way of a website hosted on anappropriate server. The consumer of energy (or other entity that wishesto verify energy readings) retrieves a public key from the device (block420). This public key may be on a label 282 or may be provided by anyother appropriate mechanism as described above. The user may then usethe public key to authenticate the information on the website (block430) and retrieve the authenticated energy readings (block 440).

In order to secure packets transmitted between them, the energymonitoring devices 120 may use a shared key. In this example, beforesending a packet to the next energy monitoring device 120, theoriginating energy monitoring device 120 encrypts the packet (or portionthereof) with the shared key. The receiving energy monitoring device 120then decrypts the packet (or portion thereof) and only forwards thepacket on to the next energy monitoring device 120 if the decryptionprocess results in valid information. In this way, energy monitoringdevices 120 or rogue devices may not insert themselves into the meshnetwork unless they know the shared key (or defeat theencryption/decryption algorithm).

The energy monitoring devices 120 may incorporate a GPS receiver orother mechanism for determining position (such as RF triangulationtechniques). The position of each energy monitoring device 120 may beincorporated and secured in packets transmitted from the energymonitoring device using techniques such as those previously described.Any receiving device may then ignore data from a device that is not inan expected geographical location. This information may also be used todetect tampering such as for instance an energy monitoring device 120being moved from its expected location. In addition, the portablecommunication device 180 may also incorporate a GPS receiver. Theportable communication device may then compare its position to that ofthe energy monitoring device it is querying in order to verify it isquerying the correct meter. This comparison may also be performed laterafter the data from the portable communication device 180 has beentransferred to a computer.

At least one of the energy monitoring devices 120 may use patternrecognition or other techniques to scan packets they are forwarding toadditional energy monitoring devices 120. These techniques may be usedto detect rogue packets or packets containing malicious code. This mayhelp prevent tampering with the system and may help prevent viruses frompropagating through the system.

A mesh network provides redundancy in communications between devices.For enhanced reliability of the network it is desirable to have morethan once communications path from each device. The computer 160 of thepresent invention may receive diagnostic information from the devices inthe mesh network such that identification of devices with only onecommunications path leading from them may be identified to the user.Additional repeaters 155, gateways 150 or energy monitoring devices 120may then be added to the system to improve reliability.

FIG. 12 shows an alternative exemplary commercial office building 100 afor use with the disclosed embodiments. The office building 100 areceives main power from a grid intertie 1200 which interconnects thebuilding's 100 a internal power distribution network with the utility'spower distribution grid. A service entrance infrastructure 1210 couplesto the grid intertie and provides multiple 3 phase buses 1220 forpowering various loads in the office building 100 a. In typicalinstallation, only one energy meter is provided in the building tomeasure power parameters of power flow from the grid intertie 1200 tothe service entrance infrastructure 1210.

Subsequent to the service entrance metering, power is distributed insidethe building through various vertical shafts either with traditionalconductors (older buildings) or via bus ducts (newer installations). Theshafts are much like elevator shafts, vertically on top of each otherspanning multiple floors, except that the shaft is only physically bigenough to allow the conductors to pass through the floors (whereas anelevator shaft is completely open).

On each floor the power is distributed further to provide energy forlighting, plugs and other tenant loads.

Most of the shared building loads 1230 of the commercial office building100 a are located on the roof. These loads include air conditioners,elevator motors, etc. The lease management office 1250 and engineeringoffice floor 1240 are typically the only areas where the building owneror operator has office space. Therefore, gateways 150, computers 160,LAN 170 and WAN 171 connections for energy monitoring use are typicallyalso located on these floors.

Energy consumption information may flow from the mesh networked devices(energy monitoring devices 120, repeaters 155 and gateways 150) throughthe computers 160, LAN 170, WAN 171 to a remote data processing center1260 where usage information such as bills may be generated. This usageinformation 1270 is then returned to the building users 1280 throughappropriate communication means. This information may also be deliveredto corporate users 1290 such as the building owners/operators. A meshnetwork or other communications connection may be made to the serviceentrance meter 1215 in order that the computer 160 and/or remote dataprocessing center 1260 may correlate the readings therefrom with thosefrom the various energy monitoring devices 120. For instance if allloads within the office building 100 a are monitored with energymonitoring devices 120, the combination of the energy monitoring devicesreadings should correlate with those of the service entrance meter 1215.

The building users may be presented with billing information thatcategorizes their actual energy usage and share of common loads by theremote data processing center 1260 by using the information from theenergy monitoring devices 120.

Three phase transformers 1205 may be provided at various points in theoffice building 100 a. In these cases it may be desirable to have energymonitoring devices 120 on both the inputs and outputs of thetransformers to account for loses therein.

In one embodiment, the office building 100 a, may contain one or morethan one electrical closet shafts 1225. These shafts may split or bewidely separated from one another. It may therefore be necessary to havemultiple mesh networks within the building that comprises separate setsof energy monitoring devices 120, repeaters 155, gateways 150 andcomputers 160. Wireline segments or other means of bridging gaps in themesh network may alternatively or in addition be used as describedabove.

When commissioning the system, battery powered mesh networking devicessuch as battery powered repeaters 155 may be temporarily installed inthe building in order to “prove” out the network and identify areaswhere particular attention will have to be paid to establishing networklinks.

In addition, in some implementations, the low power RF signals of themesh network may have difficulty traveling in a horizontal directionfrom the associated antennas of the devices 120 due to inherentlimitations in the transmissive properties of such signals. Suchlimitations may result in a restricted transmission range. However,typically the vertical transmissive properties of the RF signals areacceptable. In one embodiment, the mesh network is formed via thevertical electrical shafts which allow for the vertically radiated RFsignals to travel relatively unimpeded. The mesh network is carried tothe roof of the facility or to another area having no substantial RFimpediments, where the mesh network is bridged, either via a wired orwireless connection to other electrical shafts which have similarlyformed mesh networks. In this way, the vertical transmissive propertiesof the RF signals are advantageously utilized and reliance on thehorizontal transmissive properties are minimized. Alternatively, forbuildings such as malls with a small number of floors, but a widehorizontal expanse, mounting devices 120 and/or repeaters 155 to formthe mesh network along the roof also provides for an efficient networkstructure. Devices 120 monitoring rooftop loads such as air conditionersmay perform “double duty” by extending the mesh network as well asmonitoring a load. Repeaters 155 may be solar powered when mounted inrooftop locations or otherwise as described herein.

The following describes one exemplary implementation of a systemincorporating aspects of the present invention. One exemplaryimplementation, which employs one or more of the disclosed embodiments,utilizes the ION 6100 Wireless Metering System, manufactured by PowerMeasurement, Ltd., located in Saanichton, British Columbia, Canada,which offers outstanding quality, versatility, and functionality in alow-cost wireless power and energy metering system ideal for sub-billingapplications. This system is based on the PML ION 6100 Wireless PowerMeter/monitoring device 120 and meets ANSI C12.16 Class 1 energyaccuracy. This system may be utilized by Commercial (Office & Retail)Properties market in North America, and is ideal for customers who needrevenue-accurate measurements for tenant sub-billing.

The system includes wireless metering devices, non-intrusive currenttransformers (CTs), and a central gateway that gathers, aggregates andlogs meter data and exports it in an industry-standard XML format forintegration into any software or billing system (including PowerMeasurement's ION EEM software).

The meters collect time-stamped, interval-based consumption data (kWh)from key sub-metering or sub-billing points throughout a building, thencommunicate the information to the central gateway (PC) via aproprietary wireless 900 MHz radio network. All meters are time-alignedwith the gateway clock, so the system can also provide coincident demandreadings.

The system offers customers a lower total cost of ownership (TCO)because: wireless communications eliminate the need to run costlycommunication wire and conduit throughout a facility; easy-to-use,split-core, current transformers (CTs) simply clamp onto existing wiresfor non-intrusive current measurements, simplifying installation; theultra-compact meter design can attach to virtually any enclosure morethan four inches deep with a single bolt; and automated gathering ofmeter data removes the need for manual meter reading.

The exemplary ION 6100 Wireless Metering System offers: high quality andaccuracy, low installation costs (contributing to a lower Total Cost ofOwnership); a complete system (meters, communications, gateway)(contributing to a lower Total Cost of Ownership); industry-standard XMLdata export for easy integration into any software system (such as theION enterprise energy management system (“EEM”), manufactured by PowerMeasurement Ltd, located in Saanichton, British Columbia, Canada); andtime synchronized for coincident demand calculations.

Unlike other power meters, which are sold separately and to a wide rangeof markets, this device is made available as part of a largersub-billing solution for the commercial property market in NorthAmerica.

The exemplary ION 6100 power meter offers:

-   -   Sub-Billing and Cost Allocation        -   Costs (including usage and demand charges) can be fairly            accounted for and apportioned among tenants appropriately,            increasing tenant satisfaction and lowering operating costs.    -   Low Total Cost of Ownership (TCO)        -   The system offers customers a lower total cost of ownership            (TCO) because:            -   All necessary components can be purchased at once, on a                single P.O.;            -   Wireless communications eliminate the need to run costly                communication wire and conduit throughout a facility;            -   Easy-to-use, split-core, current transformers (CTs)                simply clamp onto existing wires for non-intrusive                current measurements, simplifying installation;            -   Simple installation ensures no disruptions to regular                business processes;            -   Ultra-compact meter design can attach to virtually any                enclosure more than two inches deep through a standard                knockout with a ½″ threaded conduit lock ring;            -   Automated gathering of meter data removes the need for                manual meter reading.    -   Reliability        -   The ION 6100 offers a reliable “self-healing” approximately            900 MHz wireless radio network.    -   Each meter can relay a signal to the next closest meter,        allowing signals to be easily transmitted from one end of a        building to another. If a meter becomes unavailable, the other        meters can communicate “around” it, so that there is no        significant disruption in data transmission.    -   Useful Data        -   Besides sub-billing and cost allocation, data can be also            used as an input to building automation and control systems,            leveraging and maximizing the value of existing systems. The            gateway can be used to capture a quick snapshot of overall            operating performance and/or identify power problems at a            particular load.        -   The ION 6100 Wireless Metering System is currently aimed at            the North American commercial office and retail properties            market, for buildings with greater than 500,000 square feet            of leasable space and at least 20 tenants.        -   The key application for this system is sub-billing, but many            commercial enterprises are also beginning to leverage these            systems as core elements of a more comprehensive EEM            solution focused on reducing energy costs and improving            their net operating income (NOI) and overall asset value.    -   Value Proposition        -   For commercial building managers and owners in North America            who need an accurate and automated system for fairly            recovering energy costs from tenants. This system combines            an accurate and reliable meter with a robust wireless            communication network to create an automated sub-billing            system with a low installation cost and a low total cost of            ownership (TCO). Unlike traditional sub-metering devices,            which must be manually read or that may lack the software            required for efficient sub-billing or more powerful            enterprise energy management. The ION 6100 Wireless Metering            System is an integrated end-to-end solution for tenant            sub-metering and a key piece of a comprehensive Enterprise            Energy Management (EEM) system

Exemplary relevant applications of the exemplary system include PrimaryApplication: Sub-Billing

Typical scenario before installing ION 6100 Wireless Metering Systemsolution: Existing No Metering Existing Metering - Situation No SystemDesired The property owner needs The property owner needs Outcome torecover the costs of to recover the costs of supplying electricity tothe supplying electricity to the individual tenants for the individualtenants for the lowest cost possible. lowest cost possible. AttemptedEnergy and demand costs Meters are manually read Approach are either notpassed either by a sub-billing through to the tenants, or serviceprovider or by a costs are allocated to the designated individual ortenants based on a common individuals employed by formula - normallybased the property management on the square footage of the company.tenant relative to the total leasable space of the building. InterferingSome States prohibit Even with existing metering Factors allocationmethods of cost that has communications recovery (Note: some ability thecost of prohibit sub-billing as implementing well). Traditionally, thecommunications can be costs to implement a sub- high. metering systemare high. Economic Tenants are getting smarter The labor and dataintegrity Consequences and asking to be billed only costs of managingthese for their own usage. manual systems are high. Allocation methodsare The lack of resolution in inaccurate and generally the data (i.e.one monthly considered unfair. Accurate kWh reading) provides no andreliable sub-billing is insight into the somewhere between being aopportunities that may be competitive and a de-facto available to bettermanage standard. costs. Allocation of coincident demand costs is notpossible.

Typical scenario after installing the exemplary ION 6100 WirelessMetering System solution: New A low TCO, highly accurate A low TCO,highly accurate Approach and reliably automated sub- and reliablyautomated sub- billing system billing system Enabling Low cost meteringdevices Low cost metering devices Factors that are inexpensive toinstall that are inexpensive to install (non-intrusive CTs, wireless(non-intrusive CTs, wireless communications) and communications) andmaintain. maintain. Powerful and user-friendly Powerful anduser-friendly data collection and billing data collection and billingsoftware for providing software for providing detailed cost data.detailed cost data. Economic Enables energy cost recovery Competitive orsustained Rewards in States that do not allow advantage relative totenant allocation methods. satisfaction. Reduces costs Competitive orsustained due to manual reading and advantage relative to tenantpotential data entry errors. satisfaction. Detailed interval Detailedinterval data enables data enables accurate accurate coincident demandcoincident demand cost cost recovery. Detailed recovery. Detailedinterval interval data enables insight to data enables insight toidentify identify energy savings energy savings opportunities.opportunities.

Secondary Applications include: Contract and Bill Validation, which canhelp customers verify that energy management improvements are generatingthe projected payback, high-accuracy measurements can also be used forutility bill verification; and Cost Allocation which can help monitorcost centers right down to the tool level, identify opportunities fordemand control, and check energy consumption patterns.

The following tables describe features and benefits of the exemplary ION6100 monitoring device as both a metering device and as a gatewaydevice.

ION 6100 Metering Device Feature Advantage Benefit ION 6100 meter, Allthe metering pieces Simple to purchase, NICTs, wireless in one neatlittle package inexpensive to install and communications operate -Installed costs of gateway $300 to $500 per metering point as comparedwith traditional sub-metering solutions Non-intrusive The ION 6100meters Low installation cost, no current & voltage can be installedwithout installation disruption transformers requiring an outage in(NICVTs/NICTs) power to the load and/or voltage displacement connectionsWireless radio No holes to drill, no Low installation costs, no networkconduit or wires to run, communication configura- communications instantand automatic tion on the device - network configuration Reliable“self-healing” network communications Exceeds ANSI Accuracy is verifiedto Costs can be fairly C12.16 (1%) national sub-metering accounted forand accuracy standards apportioned appropriately standards orappropriate local standard. 24 hour internal Data is stored on the Lowrisk of data loss data storage device as a backup in case of a temporarycom- munication interruption Devices are time Independent deviceBuilding demand charges synchronized to clocks are coordinated to can beaccurately the ION 6100 enable accurate coinci- apportioned amongtenants Gateway for dent demand calculations coincident demandcalculation

ION 6100 Gateway Feature Advantage Benefit All data is Gateway softwarecan be Data can be used for sub- collected configured to export data tobilling, as an input to building in a multiple systems automation andcontrol central systems, etc. data file and exported as requiredDiagnostic Other power, energy, The gateway can be used to data cancommunication and other capture a quick snapshot of be diagnostic datacan be viewed overall operating performance requested on the gatewayfrom any and / or identify power from device in the network problems ata particular load. devices

It is therefore intended that the foregoing detailed description beregarded as illustrative rather than limiting, and that it be understoodthat it is the following claims, including all equivalents, that areintended to define the spirit and scope of this invention.

1. An energy monitoring device for securely reporting energyconsumption, comprising: current interface circuitry operative to sensecurrent flow in at least one power line and generate a first analogsignal indicative thereof; at least one analog to digital convertercoupled with said current interface circuitry and operative to convertsaid first analog signal to a digital representation of said sensedcurrent flow; a processor coupled with said at least one analog todigital converter, and operative to calculate at least one measure ofenergy consumption based on said digital representation and store saidcalculated at least one measure of energy consumption as at least oneenergy consumption message; a memory register coupled with saidprocessor and operative to store a private key, wherein said processoris further operative to generate a digital signature based on said atleast one energy consumption message and said private key and sign saidat least one energy consumption message utilizing said digitalsignature; and a radio frequency interface coupled with said processorand operative to transmit said signed at least one energy consumptionmessage, via at least a second and a third energy monitoring device, toa remote device.